1. Field of the Invention
The present invention relates to a technology for preventing an occurrence of dew condensation in an image forming apparatus.
2. Description of the Related Art
In a tandem-type image forming apparatus including a photoconductor and a writing unit, when a temperature inside the image forming apparatus rises rapidly from a low temperature, dew condensation may occur on the photoconductor or the writing unit. It is known that an occurrence of dew condensation can be prevented by heating an image forming unit.
For heating an image forming unit to prevent an occurrence of dew condensation, Japanese Patent Application Laid-open No. 2002-215006 discloses a technique for reducing power consumption of a heater by turning on the heater when a predetermined period of time elapsed after a fixing unit is shifted to an energy-saving mode. Furthermore, Japanese Patent Application Laid-open No. 2004-61580 discloses a technique for using exhaust heat of the fixing unit for a heater for preventing an occurrence of dew condensation.
However, if toner cartridges of all colors, i.e., BK (Black), M (Magenta), C (Cyan), and Y (Yellow), are heated during night time or holidays, i.e., when the image forming apparatus is not frequently used, it is problematic that the power consumption of the heater considerably increases. Therefore, it is required to reduce the power consumption during night time or holidays.